Heres a really cool link with some neet information
http://www.seabay.org/articles/let_there_be_light_3.htm
and this if from another article
How often should I change my bulbs?
Generally speaking, ANY bulb should be changed after 2500 hours of burn time (3000 hours at most). Much after this, the intensity decreases dramatically, and you tend to have a spectral loss at the blue/UV end. Changing bulbs at a regular interval will avoid this. As an example, suppose you are burning your lights 10 hours a day. Assuming 30 days per month, you would want to change the bulbs every 8.5 months at minimum or 10 months at maximum. Do NOT assume that just because a light is bright means that it is still valuable as a light source. This is not always the case. Our eyes are far more sensitive to the red/yellow/orange areas of the spectrum, whereas the greatest loss occurs down at the blue/UV portion (a portion of the spectrum to which ours eyes are not as sensitive. That’s the reason high Kelvin bulbs look dimmer to us).
Over time, as the bulbs dim, your corals become accustomed to the lower spectral intensity. Suddenly, as you change the bulbs, these animals are blasted with higher levels of UV radiation as well as visible light. This is the primary cause of “coral burn” or coral bleaching in captive specimens. In order to avoid this, whenever you install new lighting, or when changing from a lower intensity bulb to a higher intensity bulb, you might want to raise the fixture higher over the tank. Then over a period of a week or two, slowly lower the fixture back to its original height this applies mostly to metal halide lighting as other lighting sources do not seem to produce the same effect). This will give the corals time to adjust to the greater intensity. If raising the lighting is not an option, placing a sheet of glass or UV blocking acrylic between the bulbs and the corals should suffice.
Reply With Quote
